Campylobacter jejuni is now recognized as one of the leading causes of diarrheal diseases worldwide. Approximately two million cases of C. jejuni enteritis occur in the United States each year, and the actual incidence may be even higher for at least two reasons. First, C. jejuni is a fastidious bacterium which requires microaerobic environment (5% O.sub.2, 3-10% CO.sub.2) to grow, a condition that is not available in many clinical microbiology laboratories. Second, treatment of diarrheal patients with antibiotics for any reason may kill C. jejuni, thus causing conventional diagnostic methods based on culturing viable bacteria to yield false negative results. Thus, a new diagnostic technique is needed to detect C. jejuni bacteria, whether viable or not.
PEB1A is conserved in all clinical isolates of C. jejuni. Theoretically, it is possible to diagnose C. jejuni infection by detecting the common PEB1A structure in fecal specimens using immunological methods such as ELISA and Western blot but sensitivity may be low because PEB1A is only a minor component of the bacteria. Alternatively, use of PEB1A as antigen to detect specific antibodies for diagnosis of C. jejuni infection, while promising, has limitations caused by difficulty in obtaining large quantities of enough purified PEB1A. Thus, more efficient production of PEB1A is desirable.
Prior art attempts at vaccines and therapy for C. jejuni enteritis have suffered from incomplete knowledge of the important antigen and receptor interactions discussed herein regarding PEB1A.